'NCIS' Star Sued Over BMW-Crushing Car Crash

"NCIS" star Michael Weatherly has just been sued over the gnarly car accident he got into last year -- after allegedly injuring the other driver so bad ... the guy needed serious neck surgery.

The other driver -- Ivan Romeo Mendez -- filed the lawsuit recently in L.A. County Superior Court ... claiming he had to be hospitalized after the accident, which also destroyed his BMW beyond recognition.

But that's just the tip of the iceberg -- Mendez' lawyer tells TMZ, Ivan is suing for at least $80,000 in medical expenses after he had to undergo a rhizotomy because of the crash ... a neurological procedure that severs problematic nerves in the spinal cord.

So far, no word back from Weatherly's people.